Asynchronous real-time retrieval of data

ABSTRACT

A data retrieval system includes a gateway server and an access client. The gateway server is communicatively connected to the access client through a network. The gateway server provides a presentation service (PS) and a real-time service (RTS), which cooperate with the access client to retrieve data from a data store and then provide the retrieved data to a user&#39;s remote communication device. More particularly, when a user wishes to retrieve data from the data store or to send data to the data store, the user establishes a communication connection between his or her remote communication device and the gateway server, and then requests the desired data from the gateway server. In response, the gateway server sends a command to the access client, instructing it to retrieve the requested data. The access client retrieves the requested data from the data store, and returns the retrieved data to the gateway server. The gateway server then relays the requested information back to the user&#39;s remote communication device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.12/708,277, filed Feb. 18, 2010, which is a Continuation of U.S.application Ser. No. 12/017,536, filed Jan. 22, 2008, which is aContinuation of U.S. application Ser. No. 10/770,841, filed Feb. 2,2004, and in turn claims priority to U.S. Application Ser. No.60/444,213, filed Jan. 31, 2003, entitled “Asynchronous Real-TimeRetrieval Of Data,” the entire contents of each of which are herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the asynchronous real-time retrieval ofdata. Various aspects of the present invention are particularlyapplicable to the asynchronous real-time retrieval of data from acorporate database to a remote device, such as a wireless telephone orpersonal digital assistant.

2. Description of the Related Art

Recently, digital information has become more and more important topeople of all walks of life. As the importance of digital informationhas increased, the need for convenient remote access to a variety oftypes of digital information has increased as well. For example,traveling businessmen may desire continual access to informationcontained in electronic spreadsheets, attorneys may desire access toword processing documents from a client's location, and students maywant to send or retrieve electronic mail while in school.

In order to address this need, many communication service providersallow their customers to access remote digital information through acommunication network. For example, a wireless telephone serviceprovider may allow its customers to use their wireless telephones orother communication devices to send and receive retrieve electronicmail, retrieve image information from a network, obtain contactinformation from a centralized database, or the like. Similarly, somecompanies have established remote high-speed. Internet connections, bothwired and wireless, at public locations such as restaurants, hotels, andairports, which can be accessed by a customer's computer.

While communication service providers have created an infrastructurethat potentially allows their customers remote access to digitalinformation, many practical issues still prevent this infrastructurefrom being fully utilized. For example, some customers seek to accessdigital information stored behind a barrier, such as digital informationstored in their employer's database and protected by a firewall. Withthis arrangement, if the employer's network did not support an accesstool allowing external connections through the firewall then a customerwould be prevented from accessing the desired digital informationthrough the communication service provider's network. These access toolsinclude, for example, the use of a virtual private network (VPN) orsimilar techniques for enabling secure and authenticated connectionsfrom devices not directly connected to the employer's network. Moreover,even if the employer's network supported such a tool, the customer'scommunication device could still not access the data if the user'sdevice itself was not configured to support that tool.

In other situations, a customer may attempt to use an unsuitablecommunication device to retrieve data. For example, a user may attemptto employ a personal digital assistant or wireless telephone with arelatively simple browser to retrieve a Web page with a large amount ofimage or audio data. Before the large amount of data can be fullyretrieved, the personal digital assistant or wireless telephone may“time out” and sever the connection. Alternately or additionally, theuser may seek to download more data than the personal digital assistantor wireless telephone may store.

SUMMARY OF THE INVENTION

Advantageously, various examples of the invention allow a user to moreconveniently send data to and retrieve data from a remote data storeusing a remote communication device. With different aspects of theinvention, a data retrieval system includes an in-box (IB) server,referred to hereafter more generally as a “gateway server,” and adesktop access client (DAC), referred to hereafter more generally simplyas an access client. The gateway server is communicatively connected tothe access client through a network. The gateway server provides apresentation service (PS) and a real-time service (RTS), which cooperatewith the access client to retrieve data from a data store and thenprovide the retrieved data to a user's remote communication device usinga presentation protocol appropriate to the device's capabilities.

With various implementations of the invention, the access client willcreate a connection to the gateway server. When the user wishes toretrieve data from the data store or to send data to the data store, theuser establishes a communication connection between his or her remotecommunication device and the gateway server, and then requests thedesired data from the gateway server. In response, the gateway serversends a command to the access client, instructing it to retrieve therequested data. The access client retrieves the requested data from thedata store, and returns the retrieved data to the gateway server. Thegateway server then relays the requested information back to the user'sremote communication device through the presentation server using apresentation protocol appropriate to the device's capabilities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a network environment including a system forasynchronous retrieval of data according to various embodiments of theinvention.

FIG. 2 illustrates an example of a computing system that may be used toimplement various embodiments of the invention.

FIGS. 3A-3D illustrate a flowchart showing a method for asynchronouslyretrieving data according to various embodiments of the invention.

FIGS. 4A-4E illustrate a flowchart showing a method of retrieving datafrom a data store according to various embodiments of the invention.

FIG. 5 illustrates a system for asynchronous retrieval of data employingmultiple gateway servers according to various embodiments of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic block diagram of a data retrieval system 100according to various embodiments of the invention. The retrieval system100 allows for the retrieval of data, such as data from a corporate datastore, to a remote device. As seen in this figure, the data retrievalsystem 100 includes at least one gateway (IB) server 101 and an accessclient (DAC) 103. In the illustrated example, the access client 103 ishosted by a user's computer 105. The computer 105 is located in, forexample, a corporate network environment 107 that includes the datastore 109 from which data is to be retrieved. The data store 109 may beany type of data store, such as a database that organizes data, a serverdevice that provides services to one or more client devices or acombination of the two. The data store 109 may be, for example, a LotusDomino server or a Microsoft Exchange server that manages a variety ofdata including electronic mail messages, calendar information, contactinformation and the like. The corporate network environment 107 may alsoinclude a firewall 111 or other barrier for preventing unwanted accessto the corporate network environment 107. The data store 109 may also bea publicly available data store, such as, for example, a Yahoo emailserver or the like. Still further, the data store may be a generic IMAPor POP3 mail store, or even a store employing a desired file system,such as the NTFS file system.

As shown in this figure, the gateway server 101 is communicativelyconnected to the access client 103 through a network 113, such as awide-area network. The network 113 may be a publicly accessible network,such as the Internet. Alternately, the network may be a private network(often referred to as an intranet), or a combination of public andprivate networks. The gateway server 101 provides a presentation service(PS) 115 and a real-time service (RTS) 117, each of which will beexplained in detail below. The presentation service 115 and thereal-time service 117 of the gateway server 101 cooperate with theaccess client 103 to retrieve data from the data store 109 and thenprovide the retrieved data to the user's remote communication device119.

More particularly, the access client 103 creates a connection 121 (whichmay be, for example, a persistent connection) to the gateway server 101through the firewall 111. The access client 103 then lies dormant untilit receives commands from the gateway server 101 to retrieve data fromthe gateway server 101 or to provide data to the gateway server 101.When the user wishes to retrieve data from the data store 109 to theuser's remote communication device 119 (or, alternately, to send datafrom the user's remote communication device 119 to the data store 109),the user establishes a communication connection 123 between the remotecommunication device 119 with the gateway server 101. Through the user'sremote communication device 119, the user then requests the desired datafrom the gateway server 101. In response, the gateway server 101 sends acommand over the connection 121 to the access client 103, instructingthe access client 103 to retrieve the requested data. In response, theaccess client 103 retrieves the requested data from the data store 109,and returns the retrieved data to the gateway server 101. The gatewayserver 101 then relays the requested information back to the user'sremote communication device 119. This process, together with thecomponents of the system 100, will be discussed in more detail below.

Operating Environment

As will be appreciated by those of ordinary skill in the art, thegateway server 101 may be implemented using one or more computingdevices, such as a programmable computer that may be programmed to send,retrieve and store the data files that make up electronic messages. Thistype of computer can be embodied by, for example, an electronic mailaccount server. FIG. 2 shows one example of such a programmable computersystem 201 capable of retrieving and caching electronic mail data filesfrom one or more outside electronic mail accounts. The computer system201 includes a processing unit 203, a system memory 205, and a systembus 207 that couples various system components, including the systemmemory 105, to the processing unit 203. The system memory 205 mayinclude a read-only memory (ROM) 209 and a random access memory (RAM)211.

A basic input/output system 213 (BIOS), containing the routines thathelp to transfer information between elements within the computer system201, such as during startup, may be stored in the read-only memory (ROM)209. If the computer system 201 is embodied by a personal computer, itmay further include a hard disk drive 215 for reading from and writingto a hard disk (not shown), a magnetic disk drive 217 for reading fromor writing to a removable magnetic disk (not shown), an optical diskdrive 219 for reading from or writing to a removable optical disk (notshown) such as a CD-ROM or other optical media, or a memory card 221,such as a flash memory card.

A number of program modules may be stored on the ROM 209, the hard diskdrive 215, the magnetic disk drive 217, and the optical disk drive 219.A user may enter commands and information into the computer system 201through an input device 223, such as a keyboard, a pointing device, atouch screen, a microphone, a joystick or any other suitable interfacedevice. Of course, the computer system 201 may employ a variety ofdifferent input devices 223, as is known in the art. An output device225, such as a monitor or other type of display device, is also includedto convey information from the computer system 201 to the user. As willbe appreciated by those of ordinary skill in the art, a variety ofoutput devices 225, such as speakers and printers, may alternately oradditionally be included in the computer system 201.

In order to access electronic mail accounts, the computer system 201preferably is capable of operating in a networked environment usinglogical connections to one or more remote computers, such as the remotecomputer 227. The computer system 201 may be connectable to the remotecomputer 227 through a local area network (LAN) 229 or a wide areanetwork (WAN), such as the Internet. When used in a networkingenvironment, the computer system 201 may be connected to the networkthrough an interface 228, such as a wireless transceiver, a modem, anEthernet connection, or any other suitable interface. While theinterface 228 is illustrated as an internal interface in FIG. 2, it mayalternately be an external interface as is well known in the art. Ofcourse, it will be appreciated that the network connections describedabove are exemplary, and other means of establishing a communicationslink with other computers may be used.

Use of the Presentation Service and the Real-Time Service

With various embodiments of the invention, the data retrieved from thedata store 109 may be requested and received over a wide area network,such as the—Internet. This type of communication medium is relativelyunpredictable, however, and the existing level of traffic over thenetwork may affect the speed at which the real-time service 117 receivesrequested data. Further, a request for data from the user's remotecommunication device 119 will not typically specify the size of therequested data. For example, a user may employ the remote communicationdevice 119 to request his or her most recent email message from the datastore 109 without knowing the size of the message. Accordingly, when thepresentation service 115 receives a request for data from the user'sremote communication device 119, the presentation service 115 typicallycannot ascertain when it will receive the requested data from the accessclient 103.

This uncertainty presents a problem in that the presentation service 115cannot determine in advance how long to maintain the connection 123 tothe user's remote communication device 119. Typically, the remotecommunication device 119 will maintain an idle connection for only apreset time period before severing the connection. Thus, in somesituations, the time between when the presentation service 115 requeststhe data from the real-time service 117 and when the presentationservice 115 receives the requested data in reply may be longer than theamount of time that the user's remote communication device 119 will waitfor a reply from the presentation service 115 before severing theconnection 123.

In addition, the communications network supporting the communicationdevice also may implement timeout procedures that are configuredseparately and independently from either the remote communicationsdevice 119 or the gateway server 101. These procedures may be used bycommunications service providers to prevent idle connections fromconsuming network resources that might otherwise be allocated to activeconnections. Thus, the communications network itself may timeout andsever the connection 123 to the gateway server 101 before a reply fromthe presentation service 115 has been received.

Moreover, different types of remote communication devices 119 will havedifferent waiting periods before severing an idle connection (that is, aconnection where data is not being exchanged). More particularly, sometypes of remote communication devices 119 may employ a relativelysophisticated communication software application that will maintain anidle connection for several minutes. For example, if the remotecommunication device 119 is a laptop personal computer, it may use aversion of the Microsoft Internet Explorer browser to communicate withthe presentation service 115. This type of communication softwareapplication is typically configured to receive rich data with graphicsand colors, and thus will wait a relatively long time for a reply fromthe presentation service 115 before “timing out” and severing theconnection 123.

On the other hand, a less sophisticated remote communication device 119may employ a communication software application intended to receive onlyvery simple data and that will only briefly maintain an idle connection.For example, a wireless telephone may communicate with the presentationservice 115 using a streamlined browser that receives only text data andis designed to be navigated with a keypad. This type of simplycommunication software application will typically wait only a relativelyshort period of time for a reply from the presentation service 115before timing out and severing the connection 123.

To address this discrepancy between different types of remotecommunication devices 119 and their different supporting communicationsnetworks, the gateway server 101 according to various embodiments of theinvention may employ both the presentation service 115 and the real-timeservice 117. More particularly, with various embodiments of theinvention, the real-time service 117 maintains the connection 121, whichmay be a persistent connection, to the access client 103. Thepresentation service 115 then manages the connection 123 with variousremote communication devices 119 through various communicationsnetworks. Thus, the presentation service 115 and the real-time service117 cooperate together to provide asynchronous retrieval of data fromthe data store 109 to the user's remote communication device 119. Thatis, the timing of communications between the real-time service 117 andthe data store 109 (through the access client 103) is independent of thetiming of communications between the presentation service 115 and auser's remote communication device 119.

According to various embodiments of the invention, the connection 121,the connection 123, or both may be encrypted. For example, theconnection 121, the connection 123, or both may be encrypted using theSecure Sockets Layer (SSL) protocol. The encryption may be on aconnection-by-connection basis. Thus, the connection 121 may beencrypted using one set of encryption information shared between theaccess client 103 and the real-time service 117, while the connection123 may be encrypted using another set of encryption information sharedbetween the user's remote communication device 119 and the presentationservice 115. Alternately, with various embodiments of the invention, theconnections 121 and 123 may be commonly encrypted “end-to-end,” usingencryption information shared between the user's remove communicationdevice 119 and the access client 103.

Asynchronous Retrieval of Data

Referring now to FIGS. 3A-3D, these figures illustrate a flowchart forone process that may occur according to various embodiments of theinvention when the user desires to send data to or retrieve data fromthe data store 109. As shown in FIG. 3A, in order to employ the system100, a user first installs the access client 103 on a computer that hasaccess to the data store 109 (that is, on the computer 105) in step 301.For example, if the data store 109 is a Microsoft Exchange server thatmanages the user's electronic mail messages, the user will install theaccess client 103 on a computer that has access to the user's electronicmail account on the data store 109. As part of the installation processfor some embodiments of the invention, the user may submitauthentication information. This authentication information then latercan be used to authenticate the user's identity when the user attemptsto retrieve data to or send data from the user's remote communicationdevice 119.

In many situations, the user will employ the system 100 to send orreceive electronic mail messages or other data from a data store 109maintained by the user's employer. Accordingly, the data store 109 isillustrated in FIG. 1 as being within a corporate network environment107, which may be behind the firewall 111, as previously noted. In thesesituations, the computer 105 may be the user's personal work computerthat is also within the corporate network environment 107 and behind thefirewall 111, and thus has easy access to the data store 109. It shouldbe appreciated, however, that various embodiments of the invention maybe employed to retrieve data from or send data to a data store 109located within any computing environment. Also, any computing devicehaving the desired access to the data store 109 may serve as thecomputer 105. Further, as will be explained in detail below, a user mayemploy multiple access clients 103 on different computers 105 toretrieve data from or send data to the data store 109, and multipleusers may employ a shared access client 103 on a single computer 105 toretrieve data from or send data to the data store 109.

It should be appreciated that, while the access client 103 is describedin the illustrated embodiment as a client hosted on a single computer105, various alternate embodiments of the invention may employ anyconfiguration for the access client 103. For example, the access client103 may itself be implemented by a “server” computer that servers othercomputers in a network. Thus, the access client 103 may provide accessto the data store 109 for more than one user. Further, the access client103 may provide centralized management and administration tools thatenable a system administrator (e.g., a system administrator for the datastore 109) to manage and control utilization of the access client 109 byindividual users by e.g., selecting them from a directory or companyaddress list. Moreover, the access client 103 may thus be implemented ona server that performs other functions, which may or may not be relatedto the operation of the access client 103. For example, the accessclient 103 may be implemented on a public email server, such as a Yahooor Hotmail email server, or on a private email server. Still further,with different embodiments of the invention, the operation of the accessclient 103 may be distributed among a plurality of computers 105.

Returning now to FIG. 3A, once the access client 103 has been installedon the computer 105 in step 301, the access client 103 establishes asecure communication connection to the gateway server 101 in step 303.More particularly, the access client 103 establishes a secure connection121 with the real-time service 117 hosted by the gateway server 101. Anentry for the connection, referred to as a real-time session, also iscreated in the directory 127. The directory 127 may be, for example, anOracle database or other suitable database, or a Novell directory orother suitable directory. The entry for the connection 121 identifiesboth the user and the gateway server 101 hosting the real-time service117 to which the connection 121 is made.

According to various embodiments of the invention, the connection 121may be a persistent connection that is maintained as long as both theaccess client 103 and the real-time service 117 are operating to provideservice to a user. With still other embodiments of the invention,however, the connection 121 may be established on an as-instructed orperiodic basis. Thus, various embodiments of the invention may employheuristics to determine when the access client 103 establishes theconnection 121 with the real-time service 117. These heuristics maydetermine, for example, that the access client 103 will connect everyminute (or some other time period) if it services a user (or users) whohave not frequently retrieved data from the data store 109. Theseheuristics may also determine that the access client 103 willpersistently maintain connection 121 if it services a user (or users)who have frequently retrieved data from the data store 109. Stillfurther, various embodiments of the invention may employ theseheuristics only under certain conditions, such as when network trafficfor the network carrying the connection 121 increases above a thresholdlevel, or when the real-time service 117 reaches some threshold ofsimultaneous connections 121 with multiple access clients 103.

In order to subsequently retrieve data from the data store 109 to theuser's remote communication device 119 (or to send data from the user'sremote communication device 119 to the data store 109), the userconnects to the gateway server 101 through the user's remotecommunication device 119 in step 305. More particularly, the userestablishes the communication connection 123 from the user's remotecommunication device 119 to the presentation service 115 hosted by thegateway server 101.

As will be appreciated by those of ordinary skill in the art, inaddition to personally initiating a connection with the gateway server101 and requesting data from the data store 109, one or more softwareapplications running on the user's remote communication device 119 mayalso initiate the connection 123 to the presentation service 115 hostedby gateway server 101 on the user's behalf. Depending upon the purposeand needs of the particular software application, the softwareapplication can initiate the connection 123 on a periodic, scheduled, orevent-driven basis and make one or more data requests asking to retrievedata from or sending data to the data store 109. This approach relievesthe user of the need to pro-actively initiate all connections and datarequests or transfers and greatly improves the overall user experience.

In the embodiment illustrated in FIG. 1, the user's remote communicationdevice 119 is a wireless communication device that exchanges data orvoice information over a wide-area wireless telephone communicationnetwork 125. For example, the user's remote communication device 119 maybe a wireless telephone, or a personal digital assistant (PDA) orportable computer equipped with a wireless communication unit, such as aPCMCIA card like the Sierra Wireless AirCard®. With still otherembodiments of the invention, however, the user's remote communicationdevice 119 may be connected to the gateway server 101 through anysuitable connection, including a public communication network such asthe Internet. For example, the user's remote communication device 119may alternately be connected to the gateway server 101 using a wiredconnection, such as a conventional “dial-up” or DSL telephoneconnection, a high-speed broadband connection provided by a cabletelevision service provider, or even an optical connection. Further, theuser's remote communication device 119 may be connected to the gatewayserver 101 through another communication device, such as a publicInternet kiosk. Thus, rather than connecting to the gateway server 101over the wireless network 125, the user's remote communication device119 may connect to the gateway server 101 over any suitable medium,including a wireless communication network, a wired communicationnetwork or a composite wired and wireless communication network.

Similarly, the connection 121 between the access client 103 and thereal-time service 117 can be made over any suitable medium. In theillustrated embodiment, the connection 121 is established over a public,wide-area communication network, such as the Internet. With alternateembodiments of the invention, however, the connection 121 may be theestablished over, for example, a private communication network, such asa private wireless telephone communication network. Thus, the connection121 also may be established over a wireless communication network, awired communication network, or a composite wired/wireless communicationnetwork.

As will be appreciated by those of ordinary skill in the art, a varietyof communication techniques and protocols have been developed forexchanging data between devices. For example, communications over bothhigh and low bandwidth connections may be made using well-knownextensible markup language protocols, such as the Hypertext MarkupLanguage (HTML) protocol, the Extensible Markup Language (XML) or theSynchronization Markup Language (SyncML) or other messaging-centricprotocols such as the Post Office Protocol (POP) or the Internet MessageAccess Protocol (IMAP). Similarly, communications over lower-bandwidthwireless connections (such as wireless telephone connections) may bemade using the well-known Wireless Markup Language (WML) protocol. Anysuitable protocol, including any of these known protocols, may be usedto exchange data between the remote communication device 119 and thepresentation service 115, and between the access client 103 and thereal-time service 117. Thus, communications over the connection 121between the access client 103 and the gateway server 101 may be madeusing HTML or XML pages, while communications over the connection 123between the user's remote communication device 119 and the gatewayserver 101 may be made using HTML, XML, SyncML, or WML pages, or otherprotocols including, but not limited to, IMAP and POP3. Because theequipment and procedures for communicating data between devices usingthese protocols are well-known in the art, they will not be described infurther detail here.

Returning now to FIG. 3A, the user authenticates his or her identity forthe presentation service 115 in step 307. For example, the presentationservice 115 may transmit one or more authentication inquiries to theuser's remote communication device 119. These inquiries, which may becontained on a single markup language page, may ask the user for ausername and password. In response, the user transmits the requestedauthentication information back to the presentation service 115. Ofcourse, the user's remote communication device 119 may alternately oradditionally provide one or more software applications for managing andpresenting data, which includes user interface elements for collecting,storing, and submitting authentication information to the presentationservice 115 without requiring the user to manually reenter theauthentication information for each session with the presentationservice 115.

When the user wishes to retrieve data from the data store 109, the usersends a request for the desired data over the connection 123 to thepresentation service 115 in step 309. For example, the user may requestthe header information for the most recent 10 electronic mail messagesin the user's electronic mail account on the data store 109. Thisrequest can be made using any suitable technique. For example, once theuser's remote communication device 119 has established the connection123 with the presentation service 115, the presentation service 115 maytransmit WML pages with prompts to the user's remote communicationdevice 119. These pages may, for example, contain a list of possibleinformation that can be requested by the user. After the user selectsthe prompts corresponding to the desired information, the selectedprompts are transmitted back to the presentation service 115 as arequest for the desired data. Of course, still other techniques forretrieved desired information from the data store 109 may be employed,including techniques where data is retrieved automatically by anapplication on the remote communication device 119 without requiring theuser's intervention, as previously noted.

In step 311, the presentation service 115 establishes a presentationsession for the connection 123 with the user's .cndot. remotecommunication device 119. The presentation service 115 thus associatesall subsequent communications related to the request for the desireddata with the user's remote communication device 119. For example, thepresentation session may be an entry in memory, such as a data table,associating the user's username and password with a presentation sessionvalue. The presentation session may also identify a location in memory,cache 1151, at which the desired data will be stored upon retrieval, anda flag indicating if the desired data as been stored to the cache 1151.The use of the presentation session to retrieve data from the data store109 to the remote communication device 119 will be discussed in furtherdetail below.

In step 313, the presentation service 115 checks to see if the desiredinformation has already been cached in the cache 1151. As will bediscussed in detail below, if the presentation service 115 determinesthat it already has cached the desired information then, in step 315,the presentation service 115 immediately retrieves the desiredinformation from the cache 1151 and returns the desired information tothe user's remote communication device 119. When the request for thedesired data is initially made to the presentation service 115, however,the desired data probably will not have already been cached by thepresentation service 115.

Accordingly, when the desired data is not currently in the cache 1151, arequest for the desired data is sent from the presentation service 115to the real-time service 117 in step 317. In response, the real-timeservice 117 issues a command over the connection 121 to the accessclient 103 in step 319, instructing the access client 103 to retrievethe desired information from the data store 109. Upon receiving thecommand from the real-time service 117, the access client 103 retrievesthe desired data from the data store 109 in step 321. Then, in step 323,the access client 103 returns the retrieved data to the real-timeservice 117, which in turn provides the retrieved data to thepresentation service 115 in step 325. The presentation service 115 thenstores the retrieved data in the cache 1151 in step 327.

In step 329, the presentation service 115 determines if the request forthe data is still pending from the user's remote communication device119. That is, the presentation service 115 determines if the user'sremote communication device 119 is still maintaining the connection 123in wait for the desired data. If the request is still pending, then theretrieved data is provided to the user's remote communication device 119in step 331.

Thus, if the desired data can be retrieved by the gateway server 101from the data store 109 within the idle time of the user's remotecommunication device 119, then the desired data can be immediatelyprovided to the user. In many situations, however, the gateway server101 will not be able to retrieve the desired data before the idle timefor the user's remote communication device 119 expires and the user'sremote communication device 119 terminates the connection 123. As willbe discussed in more detail below, the presentation service 115addresses these situations by responding to the user's remotecommunication device 119 before its idle time expires.

More particularly, if the desired data is not retrieved before theuser's remote communication device 119 terminates the connection 123,then the presentation service 115 will send a message to the user'sremote communication device 119 instructing the user (or the user'sremote communication device 119) to resubmit the request for the desireddata. This response may be repeated until the desired data is retrievedfrom the data store 109 and stored in the cache 1151. By using thepresentations session to associate these subsequent requests with theinitial request for the desired data, the desired data can betransmitted to the user's remote communication device 119 once it hasbeen stored in the cache 1151. That is, the desired data stored in thecache 1151 can be transmitted to the user's remote communication device119 in response to an existing request for the data (i.e., over theexisting connection 123) or when the request is resubmitted to thepresentation service 115. Accordingly, desired data can be retrievedfrom the data store 109 on a real-time basis, regardless of thedisparity between the idle time of the user's remote communicationdevice 119 and the time required to obtain the desired data from thedata store 109.

Communication with the Remote Communication Device

As previously noted, the presentation service 115 manages communicationswith the user's remote communication device 119, to ensure that theuser's remote communication device 119 does not time out withoutreceiving a reply to its request for data. FIGS. 4A-4E illustrate aflowchart showing one method that may be employed by the presentationservice 115 according to various embodiments of the invention toreliably communicate with the user's remote communication device 119.

As previously noted, in step 309 of the flowchart shown in FIGS. 3A-3D,the user sends the presentation service 115 a request for desired datafrom the data store 109. In step 401, the presentation service 115determines if the request is a new request for the desired data, or ifit is a resubmission of an earlier request for the desired data. If therequest is a new request for the desired data, the presentation service115 creates a presentation session in step 403, and then passes therequest along to the real-time service 117 to retrieve the desired datafrom the data store 109.

According to various embodiments of the invention, the process ofcreating the presentation session in step 403 includes designating thecache 1151 to be used for caching information relating to the requestfor the desired data from the user's remote communication device 119. Aswill be appreciated by those of ordinary skill, the presentation service115 may employ any memory resource available to the gateway server 101.Because the requested data will be stored in the cache 1151 forimmediate transmission to the user's remote communication device 119,however, a memory resource that can be quickly accessed to provide therequested data to the user's remote communication device 119 mayconveniently be used for the cache 1151. With various embodiments of theinvention, the cache 1151 may be encrypted or unencrypted.

The process of creating the presentation session in step 401 alsoincludes designating identification information identifying thepresentation session. This identification information is then providedto the real-time service 117 with the request for the desiredinformation. When the real-time service 117 then returns the retrieveddata retrieved from the data store 109, it also provides thecorresponding presentation session identification information. Usingthis returned presentation session identification information, thepresentation service 115 stores the retrieved data in the cache 1151associated with the presentation session. It should be appreciated thatany suitable identification information may be used to identify thepresentation session for the data request. For example, theidentification information may be a specific code or password.Alternately, with some embodiments of the invention, the identificationinformation may be the memory address of the location of the cache 1151for the presentation session.

In step 405, the presentation service 115 also initiates a timer 1153for the user's remote communication device 119 corresponding to thepresentation session. As will be discussed in more detail below, thetimer 1153 will be used to predict when the user's remote communicationdevice 119 will time out and sever the connection 123 to thepresentation service 115. Further, in step 407, the presentation service115 determines device type information for the device 119 that hasrequested the data. That is, the presentation service 115 determinesinformation about the type of device making the request that will allowthe presentation service 115 to identify operational characteristics forthe user's remote communication device 119.

With some implementations of the invention, the presentation service 115may determine only a general category into which the user's remotecommunication device 119 can be classified. For example, with someembodiments of the invention, the presentation service 115 may determinewhether the user's remote communication device 119 is employing WML,HTML, SyncML, IMAP or POP or the like to communicate. If the user'sremote communication device 119 is using HTML, the presentation service115 then determines if the user's remote communication device 119 is apersonal computer or a personal digital assistant (PDA). Thus, if theuser is employing, for example, a Toshiba PocketPC®. PDA device toaccess the presentation service 115, the presentation service 115 maycategorize that device as a personal digital assistant HTML device.

Still other embodiments of the invention, however, may determinedifferent or more detailed information regarding the user's remotecommunication device 119. For example, with some embodiments of theinvention, the presentation service 115 may determine the specificbrowser (or other communication software) being used by the user'sremote communication device 119 to communicate with the presentationservice 115, particular settings for that communication software, or anyother information that might be useful to determine how the user'sremote communication device 119 will communicate with the presentationservice 115.

With some embodiments of the invention, this device type information mayconventionally be provided by the user's remote communication device 119when it initiates the connection 123. For example, if the user's remotecommunication device 119 sends a request for data using an HTML page,that page may conventionally include information that the presentationservice 115 can use to determine the type of browser that the user'sremote communication device 119 is employing to communicate with thepresentation service 115. Alternate embodiments of the invention,however, may employ alternate techniques to provide the device typeinformation to the presentation service 115.

For example, with some implementations of the invention, the user mayspecify the device type information for the user's remote communicationdevice 119 when the user installs the access client 103 on the computer105. Alternately or additionally, the user may specify the device typeinformation using a survey or questionnaire page (such as a HTML page)provided to the access client 103 or to the user's remote communicationdevice 119. Once the user has specified the device type information withthe questionnaire page, the gateway server 101 may generate and place acookie on the user's remote communication device 119. When the user thenemploys the user's remote communication device 119 to request data fromthe presentation service 115 thereafter, the presentation service 115can solicit the device type information from the cookie on the user'sremote communication device 119 in reply. Of course, still othertechniques for determining the device type information will be apparentto those of ordinary skill in the art, and may be used with variousembodiments of the invention.

Once the presentation service 115 has determined the device typeinformation for the user's remote communication device 119 in step 407,the presentation service 115 employs that device type information todetermine the communication characteristics of the user's remotecommunication device 119 in step 409. Among various communicationcharacteristics that may be identified by the presentation service 115,the presentation service 115 determines how long the user's remotecommunication device 119 will wait for a reply to the request from thepresentation service 115 before severing the connection 123. That is,the presentation service 115 uses the device type information for theuser's remote communication device 119 to determine the idle time of theuser's remote communication device 119.

For example, as previously noted, with the illustrated embodiment of theinvention the presentation service 115 may determine if the user'sremote communication device 119 is using WML or HTML to communicate and,if the user's remote communication device 119 is using HTML, whether theuser's remote communication device 119 is a personal computer or apersonal digital assistant. If the presentation service 115 determinesthat the user's remote communication device 119 is using WML tocommunicate, then the remote device 119 is probably a wireless telephoneusing a simple browser software application. Accordingly, thepresentation service 115 may determine that the user's remotecommunication device 119 will only wait a small period of time (forexample, 5 seconds) after submitting the request to receive a reply fromthe presentation service 115 before severing the connection 123. On theother hand, if the user's remote communication device 119 is a personalcomputer employing HTML to communicate, then the user's remotecommunication device 119 is probably using a sophisticated browsersoftware application, such as Microsoft Internet Explorer. Thepresentation service 115 may therefore determine that the user's remotecommunication device 119 will wait for a relatively long period of time(for example, two minutes) to receive a reply from the presentationservice 115 before severing the connection.

Various embodiments of the invention may employ different types ofdevice type information to determine the device communicationcharacteristics, as explained in detail above. Accordingly, differentembodiments of the invention may also determine different types ofdevice communication characteristics from the device type information.For example, if the presentation service 115 employs device typeinformation that only identifies the user's remote communication device119 as one of three broad categories of devices (e.g., a WML device, anHTML personal digital assistant device or an HTML personal computerdevice), then the presentation service 115 may correspondingly identifyonly one of three broad types of device communication characteristics.For example, it may determine that all WML devices will wait only 5seconds for a reply, all HTML personal digital assistant devices willwait only 90 seconds for a reply, and that all HTML personal computerdevices will wait only 2 minutes for a reply, regardless of the specificconfiguration of any particular device.

If, however, the presentation service 115 employs more detailed devicetype information, such as the particular browser being used by theremote communication device 119, then the presentation service 115 maycorrespondingly employ more specific device communicationcharacteristics information. For example, the presentation service 115may determine that a device 119 using the Microsoft Internet Explorer,Version 6.0, will wait only three minutes for a reply from thepresentation service 115 before severing the connection 123, while adevice using a Sony-Ericsson browser for wireless GSM telephones willwait only 45 seconds for a reply from the presentation service 115before severing the connection 123. As will be apparent to those ofordinary skill in the art, the level of detail of the devicecharacteristics information may depend upon the level of detail of thedevice type information obtained by the presentation service 115.

With various embodiments of the invention, the presentation service 115may obtain the device characteristics information from, for example, alook-up table such as the device characteristics table 1155. The table1155 may be populated using any conventional technique. For example, thedevice characteristics in the table 1155 may be populated when theserver is initialized. Alternately, the gateway server 101 may populatethe table 1155 by seeking the appropriate device characteristicsinformation from a remote source, such as, for example, the Internet,for each new type of remote communication device 119 that is employed bya user.

In the illustrated embodiment, the table 1155 is a component of thepresentation service 115, in order to allow the presentation service 115to more quickly retrieve the device characteristics information.Alternate embodiments of the invention, however, may have the table 1155located in the real-time service 117, an independent database directlyor indirectly accessible by the presentation service 115, or even in theaccess client 103. Still other embodiments of the invention may employother techniques to determine the device characteristics information.For example, if the user's remote communication device 119 provides acookie to the presentation service 115 with the device type information,as discussed above, this cookie may also include the devicecharacteristics information for the device 119. Further, with variousembodiments of the invention, the use of the device information todetermine the device characteristics information may be omittedentirely. Instead, for example, with these embodiments of the inventionthe user's remote communication device 119 may provide the appropriatedevice characteristics information directly to the presentation service115 when making a request for data.

It should also be appreciated that, in addition to the idle time for theuser's remote communication device 119, the device characteristicsinformation may include other data as desired. For example, the devicecharacteristics information may identify a particular data formatemployed by the user's remote communication device 119, a transmissionspeed for transmitting the retrieved data to the user's remotecommunication device 119, or other useful information corresponding tothe device type of the user's remote communication device 119.

Returning now to FIG. 4B, when the presentation service 115 hasdetermined the device characteristics for the user's remotecommunication device 119, the presentation service 115 sets a thresholdfor the timer 1153 in step 411 using the determined devicecharacteristic information for the user's remote communication device119. More particularly, the presentation service 115 sets a value forthe timer 1153 at which the presentation service 115 will generate andsend a reply to the request for data from the user's remotecommunication device 119. The threshold value is selected to allow thepresentation service 115 time to reply to the user's remotecommunication device's request for data before the user's remotecommunication device 119 times out and severs the connection 123.

As will be appreciated by those of ordinary skill in the art, thespecific threshold set for a timer 115 can be predicated upon a varietyof factors, including the amount of time necessary to prepare and send asuitable reply. Thus, if a device 119 is using a sophisticated browserthat requires a complex reply (including, for example, graphics), thenthe threshold may be set to allow more time for a reply than when theuser's remote communication device 119 is using a simple browser thatrequires only a text reply.

For example, if the presentation service 115 has determined that theuser's remote communication device 119 is using a simple browser andwill wait only 5 seconds for a reply before severing the connection 123,then the presentation service 115 may set the threshold for the timer1153 to be 3 seconds, allowing 2 seconds to generate and send the replymessage. If, however, the presentation service 115 has determined thatthe user's remote communication device 119 is using a sophisticatedbrowser and will wait two minutes for a reply before severing theconnection 123, then the presentation service 115 may set the thresholdfor the timer 1153 to be 1 minute, 50 seconds, thereby allowing moretime (i.e., 10 seconds) to prepare and send a more complex reply beforethe user's remote communication device 119 times out and severs theconnection 123.

With various embodiments of the invention, still other factors can betaken into account when determining the threshold value for the time1153, including, for example, current traffic conditions for the network125 and the degree of reliability desired for the connection 123.Alternately, a single threshold value can be designated for eachcategory of device type. Thus, for example, all communication devices119 using WML may have a first threshold value for the timer 1153, allcommunication devices 119 that are HTML-using personal digital assistantdevices can have a second threshold value for the timer 1153, and allcommunication devices 119 that are HTML-using personal computers canhave a third threshold value for the timer 1153.

Of course, with still other embodiments of the invention, a single timeperiod can be used to determine the timer threshold value for all typesof communication devices 119, regardless of their individual devicecommunication characteristics. For example, the timer threshold valuecan be set for all types of devices so that the presentation service 115employs only a single time period for all types of devices. With theseembodiments of the invention, the determination of both the device typeinformation and the corresponding device characteristics information maybe omitted.

It should also be noted that, while steps 401-411 have been describedabove as being in a specific order, other embodiments of the inventionmay order these steps in any desired manner. For example, someembodiments of the invention may set the threshold value and initiatethe timer 1153 before relaying the request for data to the real-timeservice 117. Alternately, some embodiments of the invention may relaythe request for data to the real-time service 117 before determining thethreshold value and initiating the timer 1153. Still further, with someembodiments of the invention, the presentation service 115 may set thethreshold value for the timer 1153 before initiating the timer 1153,while, with still other embodiments of the invention, the timer 1153 canbe started before the threshold value for the timer 1153 is determined.Moreover, for example, with some embodiments of the invention, thepresentation service 115 may designate the cache 1151 after the requestfor data has been relayed to the real-time service 117, before therequest for data has been relayed to the real-time service 117, beforethe timer 1153 has been set, or after the timer 1153 has been set.

In any case, once the threshold value for the timer 1153 has been setand the request for data relayed to the real-time service 117, thepresentation service 115 then monitors the real-time service 117 in step413 for a reply containing the retrieved data and the identificationinformation identifying the presentation session corresponding to therequest for the retrieved data. If a reply is not received, then in step415 the presentation service 115 determines if the timer 1153 hasreached its threshold value. If the timer 1153 has not reached itsthreshold value, then the presentation service 115 continues to monitorsthe real-time service 117 for a reply with the requested data. If,however, the timer 1153 has reached its threshold value, then thepresentation service 115 sends a reply to the user's remotecommunication device 119 in step 417, indicating that the desired datahas not yet been retrieved from the data store 109.

More particularly, when the presentation service 115 determines that thethreshold value has been reached, it formulates and sends a reply to theuser's remote communication device 119 indicating that the desired datahas not yet been retrieved. It should be appreciated that any suitabletype of reply message may be employed by various embodiments of theinvention. For example, with some embodiments of the invention, thereply message may be a page (such as an HTML or WML page) that displaysa message to the user stating that the desired data has not yet beenretrieved. With some embodiments of the invention, the reply message mayadditionally prompt the user to manually resubmit the request for thedesired data. Thus, the reply message may display an invitation to theuser to resubmit the request, along with a command prompt to resubmitthe request. When the user activates the command prompt, associatedsoftware code in the reply page will instruct the user's remotecommunication device 119 to resubmit the request. Such automatic replyoperations are well known, and thus will not be discussed in furtherdetail. With still other embodiments of the invention, however, thereply message may simply include software instructing the user's remotecommunication device 119 to automatically resubmit the request of thedesired data. With these embodiments of the invention, the reply messagemay thus omit displaying a message to the user.

For various embodiments of the invention, the reply message will alsoinclude presentation session identification data identifying thepresentation session associated with the request. This presentationsession identification information may be the same presentation sessionidentification information provided to the real-time service 117, or itmay be different from the presentation session identificationinformation provided to the real-time service 117. Also, while thepresentation session information provided to the user's remotecommunication device 119 may conveniently be transmitted with the replymessage, it may also be transmitted in a separate communication. Forexample, the presentation session identification may be provided to theuser's remote communication device 119 immediately after the user'sremote communication device 119 has submitted an initial request fordesired information.

In any case, when the user's remote communication device 119 resubmitsthe request for the desired information, the resubmitted requestincludes the presentation session information associated with theinitial request for the desired data. Thus, when the resubmitted requestis received by the presentation service 115, the presentation service115 determines that the request matches an existing presentation sessionin step 401. The presentation service 115 then proceeds immediately tostep 413 to determine if the desired data has been retrieved from thedata store 109 and stored in the cache 1151.

If the desired data has been retrieved and cached in cache 1151, thenthe desired data is immediately returned to the user's remotecommunication device 119, as noted above. If, however, the desired datahas still not been cached in the cache 1151, then the process of steps401 and 413-417 are repeated until the desired data is retrieved fromthe data store 109, stored in the cache 1151, and then provided to theuser's remote communication device 119 in step 419.

It should be noted that, with the illustrated embodiment, thepresentation service 115 translates the retrieved data into a formatthat can be processed by the user's remote communication device 119before transmitting the retrieved data to the user's remotecommunication device 119. It should also be appreciated, however, thatthis translation can be made at any point. For example, with someembodiments of the invention, the retrieved data can be translated intoan appropriate format before it is stored in the cache 1151, while withother embodiments of the invention the retrieved data may be translatedinto an appropriate format just before it is transmitted to the user'sremote communication device 119. With still other embodiments of theinvention, however, the requested data may alternately or additionallybe translated by the access client 103, the real-time service 117, thedata store 109 or even the user's remote communication device 119itself. Still further, the translation may even be performed by acombination of these components (including the presentation service115).

The request for data may thus be submitted and resubmitted by the user'sremote communication device 119 until the desired data is retrieved fromthe data store 109 by the real-time service 117 and stored in the cache1151. If there is an error in retrieving the desired data, then thereal-time service 117 may generate an error message informing the user'sremote communication device 119 that the data cannot be retrieved. Withsome embodiments of the invention, this error message may be stored inthe cache 1151 instead of the desired data. When the user's remotecommunication device 119 then retrieves data from the cache 1151, itwill retrieve the error message informing the user that the desired datacould not be successfully retrieved from the data store 109. Still otherembodiments of the invention, however, may relay the error messageimmediately after receiving the error message from the real-time service117.

With some embodiments of the invention, the presentation service 115,the real-time service 117, or both may “pre-fetch” data from the datastore 109. Thus, various embodiments of the invention may employheuristics to predict how much data a user will request from the datastore 109 base upon, e.g., the user's previous pattern of dataretrieval. For example, some users will frequently retrieve new emailmessages from their email account. For such a user, the presentationservice 115 (or the real-time service 117) may independentlyperiodically request all new email messages for the user from the datastore 109. Accordingly, when the user employs the remote communicationdevice 119 to retrieve his or her new email messages, that data willalready be stored in the cache 1151. Still other users, however, mayonly occasionally request new email messages. For these users, thepresentation service 115 (or the real-time service 117) may notindependently request new email messages from the data store 109.

Similarly, some users will regularly request particular combinations ofdata. For example, some users will typically request retrieval of anemail message, and then immediately request retrieval of any attachmentsto retrieved email messages. With these users, the presentation service115 (or the real-time service 117) may independently request attachmentdata with any requests to retrieve new email messages for the user fromthe data store 109. Accordingly, when such a user then follows a requestto retrieve a new email message with a request to retrieve attachmentdata for the retrieved email message, that attachment data will alreadybe stored in the cache 1151.

Of course, various embodiments of the invention may employ furtherheuristics instead of or in addition to heuristics relating to retrievalfrequency or the type of data retrieved. Such heuristics may include,for example, the level of service subscribed to by a user, the size ofthe data typically retrieved, or any other desired heuristicsevaluation. Also, in addition to storing independently retrieved data inthe cache 1151, various embodiments of the invention may also go aheadand forward the independently retrieved data to the remote communicationdevice 119 without receiving an express request to retrieve that data.

Communication with the Access Client

As previously noted, the real-time service 117 retrieves the desireddata from the data store 109 through the access client 103. Moreparticularly, when the real-time service 117 receives a request for datafrom the presentation service 115, it relays that request to the accessclient 103. Because the access client 103 is hosted on the computer 105that has access to the data store 109, the access client 103 caninstruct the computer 105 to retrieve the desired data from the datastore 109. When the computer 105 has obtained the desired data from thedata store 109, the access client 103 returns the desired data to thereal-time service 117.

With some embodiments of the invention, the real-time service 117 maycommunicate with the access client 103 using conventional communicationtechniques available to the computer 105, to thereby establish theconnection 121. In some situations, however, the computer 105 will belocated in an environment shielded from unauthorized access by abarrier, such as the firewall 111 illustrated in FIG. 1. In thesesituations, the barrier may prevent many types of conventional two-waycommunication between the computer 105 (and thus the access client 103)and the real-time service 117. With these embodiments of the invention,the real-time service 117 and the access client 103 may communicateusing any suitable communication technique, such as the use of a virtualprivate network (VPN). In some situations, however, even if the barriercan be configured to allow for conventional two-way communicationbetween the computer 105 and the real-time service 117, the process ofreconfiguring the barrier may be onerous, particularly if a large numberof users are employing different computers 105 to retrieve data from aremote communication device.

Accordingly, with various embodiments of the invention the real-timeservice 117 may employ a connection to the access client 103 through thenetwork 113 that will pass through the firewall. As will be appreciatedby those of ordinary skill in the art, various firewall systems willtypically allow one or more specific access points by which a computer,such as the computer 105, may receive data from sources outside of thefirewall. For example, conventional firewalls typically designate a port(sometimes identified as Port 80) through which a computer may receivedata from outside sources. The real-time service 117 according tovarious embodiments of the invention may thus use such an access port toemploy a one-way communication connection with the access client 103through this type of designated port.

Using this one-way communication connection, hereafter referred to asthe command channel, the real-time service 117 may send instructions tothe access client 103. More particularly, the real-time service 117 maysend instructions commanding the access client 103 to retrieve and relayinformation, such as the desired information, back to the real-timeservice 117. It also should be noted that the real-time service 117 mayuse the one-way command channel to instruct the access client 103 toretrieve information from a location other than the data source 109 aswell. For example, a user may wish to add information, such as a newelectronic mail message, to the data store 109 for storage or action.Upon receiving the new data from the user's remote communication device119, the presentation service 115 (through the real-time service 117)may then instruct the access client 103 to retrieve the new data fromthe real-time service 117 for delivery to the data store 109.

Thus, with various embodiments of the invention, the command channel maybe used only to send commands from the gateway server 101 to the accessclient 103. Because a command typically will be an instruction to takesome action (e.g., retrieve headers for the first ten messages in theelectronic mail folder “inbox” of the user, retrieve today'sappointments from the electronic calendar for the user, perform a searchfor the text “Mike” in the electronic mail folder “contacts” of theuser, etc.), the commands will usually be relatively small (e.g., lessthan 1 kB). As a result of their small size, multiple commands can bemultiplexed on the command channel.

In turn, the access client 103 can send data associated with the commandto the real-time service 117 (or retrieve data associated with thecommand from the real-time service 117) over one or more alternateconnections, collectively referred to hereafter as data channels. Forexample, the commands may include a specific address to which theassociated data should be posted (or from which the associated datashould be retrieved). The command may also include a parameter that cansubsequently be used by the access client 103 to identify that itsresponse (either posting or retrieving data) is a reply to that specificcommand. Using this information, the access client 103 may then postdata to the specified address (or retrieve data from the specifiedaddress) through a different socket from the socket used by the commandchannel. Similarly, the access client 103 may also post various commandsto the real-time service 117. These commands may, for example, relate tothe authorization of additional users for the access client 103.

Thus, a reply to a command from the real-time service 117 will notinterfere with the access client's receipt of new commands from thereal-time service 117, or with the transmission of data associated withresponses to earlier commands. Advantageously, this arrangement improvesthe performance by allowing data channels to be established on as-neededbasis directly to the physical server currently serving the user'sdevice Together, the command channel and the data channels provide theconnection 121 that allows two-way communication between the real-timeservice 117 and the access client 103 through a barrier such as afirewall.

For example, the real-time service 117 may command the access client 103to retrieve the desired data from the data store 109, and then post theretrieved data, along with the presentation session identificationinformation corresponding to the request, back to a specific address.The address may be a universal resource location (URL) address for alocation maintained by the real-time service 117, thereby allowing thereal-time service 117 to retrieve the desired data from the accessclient 103. The instructions (or a preceding or subsequent instruction)may also command the access client 103 to take some action with respectto the new data, such as storing the new data in the data store 109 orsending the new data to another location.

As previously noted, when the access client 103 establishes thepersistent connection 121 with the real-time service 117, the real-timeservice 117 creates a real-time session for that connection. Thereal-time session may be, for example, a data object containing anydesired data about the user and the connection, such as the port of thecomputer 105 through which the connection 121 is established. With someembodiments of the invention, the real-time session may be stored in thedirectory 127. Alternately, the real-time session may be stored inanother suitable memory location.

For various embodiments of the invention, a proxy service may beemployed between the access client 103 and the real-time service 117(e.g., in the public wide area network 113). With this type ofarrangement, the proxy service may close the connection 121 on its ownaccord after a predetermined amount of time without an exchange of dataover the connection. Alternately or addition, other problems could occurrelating to the proxy service, causing it to sever the connection 121.It would therefore be beneficial for the access client 103 to be able todetect when the connection 121 is severed, so that it can reestablishthe connection 121. Conventional application programming interfaces fornetwork communications, however, such as conventional applicationprogramming interfaces for communicating using TCP/IP, are typically notconvenient for providing an application feedback when a networkconnection suddenly closes. Moreover, the real-time service 117 will notnecessarily know that the connection 121 has been severed until, forexample, it tries to write to the socket through which the connection121 was established.

Accordingly, with various examples of the invention, the real-timeservice 117 may regularly send “heartbeat” messages to the access client103. These heartbeats may be, for example, small groups of data packetsthat can be sent to continually maintain the one-way connection betweenthe real-time service 117 and the access client 103. By periodicallytrying to send these heartbeats, the real-time service 117 canimmediately detect when the connection 121 has been severed. Thus, bymaintaining a continuous connection between the real-time service 117and the access client 103, the real-time service 117 will be prepared toimmediately process requests for desired data from the user's remotecommunication device 119 without having to initiate a new commandchannel for each new request.

With some embodiments of the invention, the heartbeat may include dataindicating to the access client 103 when the next heartbeat from thereal-time service 117 should be received. If the access client 103 thendoes not receive the next heartbeat within the indicated time period(and any additional buffer period, as desired), then the access client103 can conclude that the connection 121 is severed and needs to bereestablished. Also, because the heartbeat is generated by the real-timeservice 117, the time value indicating the rate of the heartbeat can becontrolled by the real-time service 117. More particularly, the ratedata for the heartbeats can be adjusted by the real-time service 117based upon, for example, the amount of traffic being handled by thegateway server 101. Thus, the heartbeat is dynamically schedulable.

For some implementations of the invention, the scheduled rate of theheartbeat may be the same for every connection 121. Alternateembodiments of the invention, however, may have two separate intervalsfor heartbeats. More particularly, some embodiments of the invention mayhave one heartbeat rate for active presentation sessions where a user ispresently using a communication device 119 to communicate with thegateway server 101, and another heartbeat rate for inactive sessions.This arrangement can provide a quicker connection error detection timefor sessions where a user will notice when the connection 121 iserroneously severed, and a less resource intensive connection errordetection time where a user will not immediately notice when theconnection 121 has been erroneously severed.

Multiple Use of the Access Client

While the use of the access client 103 was described above withreference to a single access client 103 accessing the data store 109,various embodiments of the invention may have multiple access clients103 communicating with the gateway server 101. That is, each of aplurality of users can maintain an access client 103 communication withthe gateway server 101. Moreover, a user can employ multiple accessclients 103 to communicate with the gateway server 101.

Additionally, various embodiments of the invention may allow a singleaccess client 103 to service more than one user. For example, with theseembodiments, when a user installs the access client 103 on the computer105, the access client 103 may inquire as to whether the user wants todelegate remote access to the user's data in the data store 109 throughanyone else (i.e., another user employing a different access client103). If the user would like the ability to access desired data in thedata store 109 through another user's access client 103, then the accessclient 103 may facilitate that arrangement.

For example, if the access client 103 is being employed in a corporatenetwork environment as illustrated in FIG. 1, the access client 103 mayprovide the user with a list of other persons having access to thecorporate data store 109 (e.g., everyone in a corporate email server).When the user selects another person from the list, the access client103 may, e.g., arrange for the selected person to receive an emailreporting his or her selection (along with instructions on how to obtainand install an access client 103, if necessary). The user's accessclient 103 may also convey an encrypted message to the selected person,either by electronic mail or by another transmission technique. Theencrypted message contains the information necessary to obtain theuser's access to the data store 109. Thus, if the selected person agreesto provide access to the data store 109 for the user, the selectedperson's access client 103 can employ the access information containedin the encrypted message to obtain the user's access to the data store109.

Advantageously, with some of the embodiments of the invention describedabove that employ a one-way command channel, the one-way command channelcan service multiple users of the access client 103. More particularly,commands corresponding to different users may be multiplexed over thesingle command channel. With this arrangement, when the access client103 establishes the connection 121 with the real-time service 117, itidentifies the users that it is serving to the real-time service 117.

Use of Multiple Gateway Servers

While the previous discussion described the user of only a singlegateway server 101 for ease of understanding, many implementations ofthe invention would employ multiple gateway servers 101, as shown inFIG. 5, to both increase capacity and redundancy. For example, someembodiments of the invention may employ gateway servers 101 in an N+1architecture, including as many gateway servers 101 as needed for adesired capacity, plus an extra gateway server 101 for redundancy.

A conventional N-tier Web service system may typically have between oneand four tiers, depending upon the purpose of the service. For example,a conventional Web service system may include a first-tier Web server, asecond-tier application server, and then a third-tier database server.In general, a user may access such a Web service system by presentingthe Web server tier with a request, which then flows to the applicationserver, and onto the database server in a vertical manner. This type ofconventional network will often include one or more load balancers thatroute incoming requests based upon the current use of each server (i.e.,the load balancer will route incoming requests to servers that are lessoccupied).

With various embodiments of the invention, however, each user has atleast one access client 103 installed on a computer 105, which in turnestablishes a persistent connection to a gateway server 101. Thus, whena user employs a remote communication device 119 to transmit a requestto the data retrieval system 100′, it would be more efficient tospecifically route the request to the gateway server 101 that hasalready established a persistent connection 121 to the user's accessclient 103.

Advantageously, various implementations of the invention mayconveniently match a user's incoming request to send or retrieve datawith the user's access client 103. As noted above, when an access client103 connects with a real-time service 117, the real-time service 117creates a real-time session for that connection. While a real-timesession exists for a persistent connection 121, it may exist acrossmultiple requests from remote communication devices 119. That is, when arequest from a remote communication device 119 is received by thepresentation service 115, it can be mapped through a real-time sessionto the real-time service 117 maintaining the connection 121 to theuser's access client 103. Moreover, each time that the request issubsequently received from the remote communication device 119, it canagain be mapped back to the proper real-time service 117 through thereal-time session. Thus, these embodiments of the invention provide acollocation process to collocate a user's presentation session,maintained by a presentation service 115, with the user's real-timesession corresponding to the persistent connection established betweenthe user's access client 103 and a real-time service 117.

Referring now to FIG. 5, with collocation, when an access client 103A isturned on, it negotiates a secure connection to a real-time service 117provided by a gateway server (e.g., the real-time service 117A providedby gateway server 101A). In the process of establishing this connection,information pertaining to the connection is stored in the directory 127.For example, when a user USER1 employs the access client 103A, thereal-time service 117 may note that USER1 has established a connectionfrom the access client 103A to gateway server 101A (or to real-timeservice 117A). It should be noted that, with some embodiments of theinvention, a user may delegate his or access to a data store (e.g., datastore 109A in FIG. 5) to multiple access clients 103 as described above.If a user thereby is associated with connections to multiple real-timeservices 117, then suitable heuristics may be employed to select oneconnection to a gateway server 101 that is preferable to the others forthe purpose of collocating a presentation session with a real-timesession.

When a user subsequently employs a remote communication device 119 to,e.g., submit a request for data from the data store 109, thepresentation service 115 receiving the request will initiallyauthenticate the request, as discussed in detail above. For example, aspreviously noted, the presentation service 115 may provide the user'sremote communication device 119 with an authentication user interfacerequesting the user's name, password, etc. Once the remote communicationdevice 119 (i.e., the user) has been authenticated, the presentationservice 115 makes a query to its associated real-time service 117, whichin turn queries the directory 127 as to the gateway server 101 (or,alternately, the real-time service 117) corresponding to the user. Morespecifically, the real-time service 117 may query to the directory 127whether the user has established an existing connection 121 between anaccess client 103 and a gateway server 101, and if such a connection 121currently exists, which gateway server 101 is maintaining the connection121.

If, for example, a request for data from USER1 is initially routed togateway server 101B, by querying the directory 127 the gateway server101B can determine that the user's access client 103 is currentlyconnected to the gateway server 101A (i.e., to the real-time service117A). Based upon this information, the presentation service 115Bgenerates a redirect response for the remote communication device 119.The redirect response may be device specific, but may not require anyspecial software. Instead, the response may be, for example, aconventional HTML, WML or HDML redirect command. The redirect responsethen causes the remote communication device 119 to issue its subsequentrequests for the desired data specifically to the gateway server 101A.More particularly, the redirect response may, for example, provide theremote communication device 119 with software instructions, such an HTTP“cookie.” These software instructions contain routing information (or,alternately, are themselves routing information) to be included insubsequent submissions of the request for the desired data.

Accordingly, when the remote communication device 119 resubmits arequest for desired information, the routing information can be used toroute the request directly to the presentation service 115 associatedwith the real-time service 117 maintaining a connection to the user'saccess client 103. For example, as shown in FIG. 5, a data retrievalsystem 100′ according to various implementations of the invention mayemploy one or more load balancers 501. These load balancers 501 routeboth incoming data retrieval requests and incoming data submissionrequests from remote communication devices 119 to a gateway server 101.With these embodiments, when a load balancer receives a request, itfirst checks to determine if the request contains routing information,such as a cookie as described above. If the request does not containrouting information, then the load balancer 501 assigns the request to agateway server 101 based upon the current load distribution of all ofthe gateway servers 101, as known in the art. If, however, the loadbalance 501 determines that a request does contain routing information,then it routes the request to the gateway server 101 identified in therouting information.

As will be appreciated by those of ordinary skill in the art, with thisarrangement each load balancer 501 may have a public network address,such as a public Internet protocol (IP) address. The gateway servers 101behind the load balancers 501 may then have virtual network addressesthat cannot be directly accessed from outside of the network. For theseimplementations of the invention, the routing information will providethe virtual network address for the desired gateway server 101, and theload balancer 501 receiving a request containing the routing informationcan then map the request to the identified gateway server 101.

With various examples of the invention, the redirect response may alsocontain additional “handoff” information to be inserted into thesubsequent requests for the desired data. When the routed gateway server101 then receives a subsequent request for the desired, it can determinefrom the handoff information that the request is a handoff from anothergateway server 101. The handoff information may also contain a timestamp, so that the routed gateway server 101 can confirm that thehandoff was recent. Using this information, it will associate therequest with a presentation session on the initial gateway server 101.The routed gateway server 101 can thus collocate the presentationsession from the presentation service 115 of the initial gateway server101 to its own presentation service 115, so that its own presentationservice 115 returns the desired data to the remote communication device119 when it is retrieved.

According to still other embodiments of the invention, the routedgateway server 101 may use the handoff information to employ theauthentication performed by the initial gateway server 101, therebyavoiding requiring that the user reauthenticate himself or herself.Accordingly, for these embodiments, the handoff information may beencrypted, to prevent unauthorized users from creating false handoffinformation to avoid authentication. Of course, the handoff informationmay be encrypted even if the routed gateway server 101 does not employthe authentication performed by the initial gateway server 101. Also, itshould be noted that, with various embodiments of the invention, thecollocation process can alternately be performed by the load balancers501, but this may require customized code.

Thus, referring back to the above example for USER1, after a request fordata from USER1 is initially routed to gateway server 101B, the gatewayserver 101B may determine from a query to the directory 127 that theuser's access client 103 is currently connected to the gateway server101A (i.e., to the real-time service 117A). Accordingly, the gatewayserver 101B provides a redirect response to the remote communicationdevice 119A with handoff information. The handoff information willinclude routing information, such as, e.g., a virtual network address,for the gateway server 101A. The handoff information may also beencrypted, and may include a time stamp and, e.g., confirmation ofUSER1's authentication. When USER1 resubmits requests for the desiredinformation, the new requests will include the handoff information.Accordingly, when the load balancer 501A receives the resubmittedrequests, it will route the requests to the gateway server 101A forhandling.

As will be appreciated by those of ordinary skill in the art, there maybe some situations where this collocation process may not be employed.For example, a user may initially employ a first access client 103 toretrieve data. If that first access client 103 then fails before thedata is retrieved, the user may be forced to employ a second delegatedaccess client 103 to retrieve the information. In this scenario, itwould not be desirable to reroute subsequent requests to another gatewayserver 101, as the gateway server 101 corresponding to the first accessclient 103 may already have some or all of the requested data in thecache 1151. Also, collocation may not be desirable when a user firstsigns up to the data retrieval system with the computer 105, but doesnot have an access client 103 installed yet.

It also should be appreciated that, with different embodiments of theinvention, a separate locator service may perform one or more of thecollocation functions instead of the presentation service 115. Forexample, with some embodiments of the invention, a locator service mayquery the directory 127 to determine the gateway server 101 to which theuser's access client 103 is currently connected, and then generate acorresponding redirect response for the remote communication device 119.

Of course, various embodiments of the invention may alternately oradditionally employ conventional remote call procedures to associate apresentation session maintained by a presentation service 115 on agateway server 111 with a connection 121 maintained by a real-timeservice 117 on a different gateway server 101. Such remote callprocedures may be employed, for example, instead of the collocationprocess described above, or if the collocation process fails for somereason.

Secure Communication Between the Access Client and the Real-Time Server

To establish a secure connection to a computer, a browser will typicallyuse an encryption protocol, such as the Hypertext Transfer ProtocolSecure, which employs the Secure Sockets Layer (SSL) encryptiontechnique. With this protocol, encryption key certificates arepreinstalled, and public key and private keys are used during a“handshake” process to negotiate a session key for the connection. Withan SSL handshake, a third party cannot determine the session key, evenif all of the exchanged data is intercepted. This type of protocolrequires a great deal of resource overhead to begin, however, andrequires a great deal of resource overhead to maintain. Moreover, withvarious examples of the invention, the presentation service 115 may beimplemented using a conventional Web server, but the real-time service117 may be implemented using a different type of server. With thisarrangement, the real-time service 117 may use HTTP and/or HTTPScommunications, but only to deliver messages through firewalls (e.g.,for requests to Port 80, which conventionally are passed by firewalls).

Accordingly, it would be beneficial to allow the access client 103 andthe real-time service 117 without maintaining an SSL session.Advantageously, various embodiments of the invention allow the accessclient 103 to communicate with the real-time service 117 without havingto maintain an SSL session. According to these embodiments, the loadbalancers 501 also serve as encryption protocol terminators in additionto load balancers. That is, the load balancer may have SSL software orhardware (e.g., SSL accelerator cards) that handles SSL communicationsvery quickly. When the load balancer passes a communication onto agateway server 101, the communication thus is decrypted to a regularHTTP format (i.e., the load balancer 501 decrypts the communicationbefore passing it to the gateway server 101). These specialized loadbalancers are known in the art and may be obtained from a variety ofsources, and thus will not be discussed in further detail.

When the access client 103 attempts to establish a connection to thereal-time service 117, it does not communicate directly with thereal-time service 117. Instead, the access client 103 initiallytransmits an encrypted message, such as a HTTPS message, through a loadbalancer 501 to a presentation server 115. The HTTPS message is receivedat the load balancer 501, which decrypts the message and routes themessage to a presentation service 115 as a HTTP message. Moreparticularly, the load balancer 501 routes the request to thepresentation service 115 of a gateway server 101 according to itsbalancing algorithm (e.g., to the gateway server 101 that is the leastbusy). The presentation service 115 then calls into the real-timeservice 117 to report that the access client 103 will soon be providinga request to establish a connection.

In response, the real-time service 117 creates an entry in a list ofpending connections (e.g., a table of access clients 103 that will soonbe connecting to the real-time service 117). In response, a uniquesession encryption key is generated (e.g., a 128-bit key), which isunrelated to the initial SSL communication between the access client 103and the load balancer 501. Any desired encryption algorithm, such asRC4, may be used to generate the encryption key. The entry in the tablewill thus include the identity of the access client 103, a publicsession identification and a private encryption key.

The presentation service 115 then sends an HTTP reply that contains theaddress (such as a universal resource location (URL) address)corresponding to the real-time service 117 to which the access client103 should connect. The reply also includes the public sessionidentification and the private encryption key. The access client 103 canthen transmit a message to the real-time service 117 using the address(e.g., using a URL of the form http://www.gateway.com/real-timeserversessionID=xxxxxx). Using this arrangement, the message sent from theaccess client 103 to the real-time service 117 may be an unencryptedHTTP message, but the data in the message can be encrypted using theprivate encryption key. The real-time service 117 can then use thesession identification in the message to locate the appropriate entry inthe table with the corresponding private encryption key. The real-timeservice 117 will then decrypt the contents of the message with theprivate encryption key.

Thus, the access client 103 and the real-time service 117 cancommunicate without maintaining an encryption session. Instead, theaccess client 103 and the real-time service 117 can use the publicsession identification and the private encryption key to securelycommunicate. Moreover, by handing off the connection directly to thereal-time service 117, these embodiments of the invention can avoidmaximizing the limit of the load balancer 501. Of course, with stillother embodiments of the invention, the access client 103 and thereal-time service 117 can securely communicate while maintaining anencryption session (such as a SSL encryption session), but also have thedata exchanged over the secure connection separately encrypted. That is,the data exchanged over the secure connection may use differentencryption information, as described in detail above, than theencryption information used to maintain the secure connection.

CONCLUSION

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques that fallwithin the spirit and scope of the invention as set forth in theappended claims.

The invention claimed is:
 1. A method of retrieving data by a wirelessdevice from an electronic mail account server via the Internet, theelectronic mail account server being arranged to receive electronic maildata on behalf of said wireless device, the method comprisingconfiguring the electronic mail account server to: receive devicecharacteristics data comprising an idle time for said wireless device atthe electronic mail account server over the Internet, said data enablingthe electronic mail account server to determine a timeout period for thewireless device; determine the timeout period for the device on thebasis of said idle time; responsive to a request for electronic maildata from said wireless device, configuring a timer at the electronicmail account server based on the determined timeout period; and in theevent that electronic mail data have not been received at the electronicmail account server at the expiry of the timer, transmit a responsemessage to the wireless device, wherein said response message causes thewireless device to submit a further request to the electronic mailaccount server for electronic mail data.
 2. A method according to claim1, wherein said idle time is included in said request for electronicmail data from said wireless device.
 3. A method according to claim 1,wherein said idle time is derived from a request for an HTML or WML pagetransmitted independently of said request for electronic mail data.
 4. Amethod according to claim 1, in which the duration of said timeoutperiod is less than the duration of said idle time.
 5. A methodaccording to claim 1, further comprising transmitting a sessionidentifier from the electronic mail account server to the wirelessdevice.
 6. A method according to claim 5, wherein said sessionidentifier is included in said response message.
 7. A method accordingto claim 5, wherein said session identifier is included in a messageseparate from said response message.
 8. A method according to claim 5,wherein the further request comprises the session identifier.
 9. Amethod according to claim 1, further comprising configuring saidelectronic mail account server to retrieve said electronic mail datafrom a remotely accessible access data store.
 10. A method according toclaim 9, wherein the remotely accessible data store comprises one ormore electronic mail accounts.
 11. A method according to claim 9,wherein the electronic mail account server comprises a presentationservice and a real-time service, the presentation service communicatingwith the wireless device and the real-time service communicating withthe remotely accessible data store.
 12. An electronic mail accountserver for enabling retrieval of data by a wireless device via theInternet, the electronic mail account server being arranged to receiveelectronic mail data on behalf of said wireless device, the electronicmail account server comprising: an interface for receiving dataindicative of device characteristics comprising an idle time for saidwireless device over the Internet, said data enabling the electronicmail account server to determine a timeout period for the wirelessdevice; a processing unit arranged to: determine the timeout period forthe device on the basis of said idle time; responsive to a request forelectronic mail data from said wireless device, configure a timer basedon the determined timeout period; and in the event that electronic maildata have not been received at the expiry of the timer, transmit aresponse message to the wireless device, wherein said response messagecauses the wireless device to submit a further request to the electronicmail account server for electronic mail data.